STILLWATER, Minn. - A Wisconsin veterinarian has pleaded guilty to sex trafficking charges for allegedly bringing young women over from China and forcing them to prostitute themselves at hotels and motels in the east metro.

Sixty-year-old Brian Lee Kersten of Baldwin, Wis. pleaded guilty Thursday to his role in an international sex trafficking ring as part of a plea agreement with prosecutors.

MPR News reports he's expected to be sentence to more than four years in prison next March.

In the charges, investigators describe how Kersten conspired with two individuals, one of whom he met after hiring her as a prostitute. Prosecutors allege that Kersten picked up girls at the airport when they flew in, drove them to area motels and picked up money after their transactions with customers.

An undercover sting was set up at the Woodbury Extended Stay Hotel after an employee notified police that an alleged prostitution ring was operating out of similar Extended Stay facilities across the metro. A detective was able to compile a list of emails, addresses and credit card numbers used by the alleged ring members.

On July 30, a night clerk at the Woodbury Extended Stay alerted police that a young Asian female had checked in accompanied by a white male in his late 50s or 60s, later identified as Brian Kersten. The clerk said she spoke little English, and signed in using Chinese characters. Undercover officers, using Backpage.com, made arrangements for a "massage" at the hotel, and were directed to room 210.

On arrival, the officers identified themselves as police, and questioned the young victim with the assistance of an interpreter. The victim told them she had been promised work in a massage parlor after arriving in Minnesota from Georgia, but instead was taken to the Woodbury Extended Stay and forced to engage in prostitution there.

The victim identified another individual who helped in the scheme, and when questioned by police that man identified Kersten and described his role in the trafficking operation. Investigators viewed surveillance tape from the date the young victim arrived at the airport and saw Kersten, the victim and another woman climb into a truck whose plates traced to Baldwin Veterinary Center, and a vehicle belonging to Kersten.